MongoDB has been powering Craigslist's archive since May 2012, initially with a cluster of replica sets and sharding to handle growth. The system has grown from 5 billion documents to over 3 billion documents, with the addition of new documents continuing to increase capacity. The use of replica sets and sharding has proven effective in handling machine failures and growth, allowing for easy addition of new nodes to the cluster as needed. While some initial adjustments were necessary to integrate MongoDB with existing management tools, the team found that MongoDB was largely self-sufficient and required minimal maintenance. Looking ahead, Craigslist plans to test MongoDB in new roles and present their experiences at a conference later this year.